Magneto



Jan. 29, 1929.

l. E. HENDRICKSON MAGNETO '5 Sheets-Sheet 2 Filed Feb. 9, 1927 J ZZ/Z\INVETVTOR. x1 Am A? BY ffl m ATTORNEYS.

Jan. 29, 1929. 1,700,677

7 I. E. HENDRICKSON' MAGNETO Filed Feb- 1927 3 Sheets-Sheet 3 PatentedJan. 29, 1929.

UNITED STATES PATENT A OFFICE.

ERA E. HENDRICKSON, OF WEST SIRINGFIELD, MASSACHUSETTS, ASSIGNOB. TOWICO ELECTRIC COMPANY, OF WEST-SPRINGFIELD, MASSACHUSETTS, A CORPORATION61 MASSACHUSETTS.

NIAGNETO.

Application filed February ticularly suitable for use in a magneto ofthe general type set forth in United States Letters Patent No.1,634,135, granted June 28, 1927, to Phelps Brown. Such magneto is of:two unit type having two recipro.- eating arniatures workingsubstantially in aiternation and the two units are connected so thateach contributes to and assists in the work the other.

The improvements of this invention are intended for use in such magnetosand are also capable of use in other magnetos of the reci oocatingarmature ty e and in certain as the invention can he used equally wellsingle unit magnetos. These improvents also primarily designed andparticularly advantageous for reciprocating ariature magnetos which areintended for use w ch nines operating at considerably higher I thestationary engines, with this type of magneto has most ifre- :t uentiybeen employed heretofore. For exampie, the magneto, hereinafterdisclosed, is l a use with the engines of tractors trucks and isdesigned to be soc is from MOO to 1800 R. P. M. one service andintermittently at hi -her speeds. The speeds, referred to, intended inany sense as limits. They ntioned merely to illustrate a condihich hasto be met in order to adapt a .s. ,iieto of the stated type to new andbroader iieids of service. mature actuating mechanisms, funcnallysimilar to that of this invention so far as or-cad purposes areconcerned, have provided heretofore invarious forms. and those aresatisfactory for their intended a given prior art type of are -"owever,mature "ctuating mechanism, which opersatisiactcrily in a low speedmagneto, not necessarily give satisfaction with a magneto operating atmuch higher speeds.

The mechanism, quiet in operation at low speeds, become unduly noisywhen operat high speeds.

The present invention, in one of its broad aspects, is directed to, andhas for an 0036013,

9, 1927. Serial No. 166,825.

the provision of an armature actuating mechanism for a magneto of thetype described which will admit of operation at high speeds in acommercially satisfactory manner.

In this connection it is an object of the invention to provide anarmature actuating mechanism for a magneto of the type described, whichembodies an improved system of levers, whereby a relatively small forceapplied from the drive shaft will be multiplied during its transmissionto the armature so that an adequate and much larger force is availableto overpower the resisting force of magnetic attraction and move thearmature away from its poles.

An important characteristic of the armature actuating mechanism lies inthe avoidance, so far as possible, of im which, while perhapsinsignificantin low speed operation, would in high speed operationproduce objectionable'noise. Coupled with this characteristicandincident thereto and to the improved leverage system, is thereduction of strains and consequent wear" on the parts of the mechanism.The primary purpose, however, is to render the magneto easy to operateand relatively quiet in operation at the higher speeds.

Another object of the invention relates to the improvement of theoperation of a magneto of the two unit type, when working at very lowspeeds, such as cranking speeds for example,the improvements resultingin the production of a longer and fatter spark from the magneto atcranking speeds than could be produced at cranking speeds from themagneto of said copending application.

acts or blows Another object of the invention relates to I an improveddisposition and relative arbricat-ion; and of keeping the dimensions of.

a compact grouping of s I the magneto within standard limits recognizedin and demanded by the trade.

There are many details contributing to the accomplishment of the aboveobjects and these, as well as other objects and advantages, will appearin the following description and will be pointed out in the appendedclaims.

The invention will be disclosed with reference to the accompanyingdrawings, in which Fig. 1 is a front elevational view of a mag netoembodyin the invention,-the casing of the magnet-o being shown insection to reveal the interior;

Fig. 2 is an end elevational view looking from the left hand end of Fig.1,the casing being shown in section;

Fig. 3 is an exterior end elevational view looking from the right handend of Fig. 1;

- Fig. 4 is a cross sectional view taken on the line 1-4 of Fig. 1 butdrawn to a larger scale' Fig. 5 is a fragmentary cross sectional viewtaken on the line 5.5 of Fig. 1 but drawn to a larger scale;

Fig. 6 is a sectional elevational view taken on the line 6-6 of Fig. 2but drawn to a larger scale;

Fig. 7 is a sectional bottom plan view taken on the line 7-7 of Fig. 1but drawn to a larger scale F ig 8 is a diagrammatical view illustrativeof the electrical circuits and connections'of the magneto;

' Fig. 9 is a schematic view showing the control device positioned toeffect spring drive of the armature;

Fig. 10 is a detail view, partly in section, of the drive shaft of themagneto;

Fig. 11 is an enlarged detail of one of the driving cams; and a Fig. 12is a fragmentary cross sectional view taken on the line 1212 of Fig. 6.

In order to best illustrate the many advantages of the armatureactuating mechanism of this invention, it has been shown as embodied ina magneto of the two unit ty e having two reciprocating armatures. A ulldisclosure of such magneto will be given in order to show the inventionin one complete and operable embodiment capable of satisfying theconditions above stated. The invention is not, however, limited to usewith the particular magneto disclosed herein for illustrative purposesbut is capable of use with many other magnetos of .the reciprocatingarmature type differing specifically from that disclosed. Neither is'theinvention, in all its aspects, confined to a magneto having two armatures. While such construction is important and preferred, there aremany features of the invention, as pointed out in the a pended claims,which are,'or may be, entirely independent of the two armaturearrangement.

Referring now to the construction of the particular-magneto, the twounits thereof are connected to work in cooperative relation so that eachcontributes to and assists in, the work performed b the other. These twounits are supporte from a common frame, driven from a common driveshaft, utilize a common source of magnetic flux and are controlled bothmechanically and electrically by common means. structurally the unitsare alike. A description of one will therefore suflice for both and thecorresponding parts of the second unit will be designated by the samereference numerals primed.

Each unit includes a pair of cores 12 or magnetic pole pieces (Fig. 1)which are vertically disposed in spaced parallel relation and the upperends of which are connected to opposite poles of a source of magneticflux, herein exemplified by permanent bar magnets 13. The cores, ofcourse, are built up from suitable laminations in the usual mannerexcept that their upper ends are so shaped as to encompass the polarends of the magnets and afford oppositely disposed recesses to receivethe same. Between the laminations of cores 12 and those of cores 12 (thelatter being located in back of but spaced from cores 13) are otherlaminations 14 (Figs. 2 and 6), which fill the space therebetween, asclearly shown in Fig. 2, and which are shaped correspondingly with theupper ends of the core laminations to afford magnet receivingrecesses,-the whole affording two long, oppositely disposed recesses forreceiving oppositepolar ends of three stacks of permanent bar magnets.The magnets of each stack are held in place by wedges 15, which aredriven in between two adjacent magnets of each stack and thereby forcethe upper andlower magnets of each stack firmly against the ends of thereceiving recesses in the laminations. The laminations of cores 12 and12 and the laminations 14 are suitably clamped together, as by a seriesof bolts 16. These bolts also act to secure opposite ends ofnon-magnetic cross bars 17 and 17 (Figs. 1 and 6) to the upper ends ofcores 12 and 12, and these cross bars serve to hold the cores of eachset in proper spaced relation. The lower ends of the cores, as shown inFigs. 1 and 7 are received in recesses formed in a horizontallydisposed'frame member 18 and are clamped in such recesses by screws 19.The cores extend downwardly a short distance below frame 18 and theirbottom faces, which constitute magnetic poles, are adapted to beintermittently connected and disconnected by a reciprocating armature20.

Each unit also includes two primary coils 21 (Figs. land 7) encompassingeach core 12, and two secondary coils 22, one encompassing each coil 21.The coils 21 and 22 and the corresponding coils 21and 22' are housed inrecesses formed in a common block 23 of bakelite or other similar orsuitable material, which block fitssnugly between frame 18 and the crossbars 17. The primary coils,

21 may be connected in any suitable way to function as one chokewinding. As shown in Fig. 8, they are connected in electrical series bya wire 24. The two choke windings, comranged in upper and lower pairs.

prising the connected coils 21 and .the connected coils 21 arecontrolledby a single interrupter, comprising relatively movable breakerpoints 25 and 26. One terminal of each choke winding is grounded, asindicated in Fig.8, and the point 25 which, as will appear, is incontact with metallic parts of the machine, is likewise grounded. Theother terminal of each choke winding is connected by a wire 27 to thebreaker point 26, which as will appear is insulated from the metallicparts of the machine. A condenser 28 is provided, one terminal of whichis grounded and the other connected by a wire 29 to breaker point 26.

The secondary coils 22, constituting the generating winding, aresuitably connected, as in electrical series. by a wire 30 and the twogenerating windings, comprising the connected coils Q2 and the connectedcoils 22' are connected in any suitable way so that the currentssimultaneously produced in each are merged. As shown, the two windingsare connected in series by a wire 31 so that the electromotive forceproducedin each is added. The terminals of the generating winding areconnected to a suitable distributor D, which functions to successivelyconnect the generating winding at properly timed intervals to a seriesof spark plugs s.

The distributor, illustrated herein; involves an insulating panel 82(Fig. 6) which is secured to one end of frame member 18 and carries fourcontacts 33 (Figs. 1 and 6) ar- An insulating arm 34, pivoted to frame18 at 35 (see also 8), oscillates back and forth between these pairs ofcontacts and carries conducting pieces 36 and 37 which simultaneouslyengage one contact of each pair. The two terminals of the generatingwinding are thus successively connected to pairs of spark plugs but theplugs of each pair are arranged in series and one of them produces aspark on the firing stroke while the spark produced by the other occursnear the endof the exhauststroke. An insulating block 38, held in placeby the casing C of the magneto, encompasses the contacts 33 and hassockets to receive the spark plug wires 39. Block 38 carries springs 40to connect such wirest-o the contacts 33. The construction and operationof the distributor is not essential to the present invention and isherein shown and briefly referred to merely to complete the descriptionand disclosure of the ignition apparatus. 1

The interrupter, referred to, is mounted near that end of the machineopposite from the distributor. The interrupter is supported from thecenter of a cross bar 41 (Fig. 5) which in turn is supported nearopposite ends, through the intermediary of spacing sleeves 42, fromposts 43, which are formed integrally with an upstand from member 18.Screws 44, passing through bar 41 and sleeves 42, are threaded intoposts 43 and serve to clamp bar 41 thereto. The central portion of bar41 has an opening therein into which a bushing 45 is tightly driven.This bushing slidably receives a tubular interrupter casing 46, which isprovided exteriorly with upper and lower flanges 47 and 48. A springwire 49, secured at .its ends to bar 41 by the screws 44 described, isbent so as to afford two legs, which extend vertically upwardly from thebar onopposite sides of casing 46, and a connecting horizontallydisposed portion, which is coiled around the casing. Upon this coiledportion rests the upper flange 47 of the interrupter casing, whereby thelatter is yieldingly urged upwardly into the illus* trated position. Itcan be moved downwardly, when required, against the tension of spring 49by means later to be described, which means engages the lower flange 48of the casing 46 anc serves to control the vertical position of thelatter.

The upper end of casing 46, which is closed serves to support thebreaker point 26,the latter being adjustably fixed to and insulated fromsaid end. The other breaker point 25 is fixed to the upper end of aplunger-50, which slidably fits the bore of casing 46. The plunger 50 isadjustably fixed to a threaded stem 51 and the lower end of the latterhas a flange 52 (Fig. 6) which rests upon the free end of a fiat spring53, secured to frame member 18 as shown in Fig. 6 and tending to moveplunger 50 upwardly.

Referring now to the armature operating mechanism, with which thisinvention is primarily concerned, the armature 20 is fixed by bolts 55(Figs. 1 and 7) to an arm 56. These same bolts also serve to fasten aplate 57 to arm 56,-such plate serving to operate breaker point 25 aswill later appear. The arm 56, at one end, is pivotally mounted on astud 58, which is fixed to a post 59 located beyond one end of armature20. This postdepcnds centrally from frame 18 and serves to support oneend of the latter from, and in spaced relation with, a base plate 60.The other end of frame 18 is supported from base plate 60 by an endframe 61, which is secured by screws 62 (Fig. 2) to said end. Thearmature hinge arm 56 extends along the inner side face of its armatureand well beyond the opposite end thereof. The two arms 56 and 56 headjacent and in spaced parallel relation except for their free endswhich are offset outwardly and terminate with parallel c lindrical ends63 and 63. Such ends are isposed closely adjacent the endframe 61.

Both the armature hinge arms 56 and. 56' are operated from a commondrive shaft 65, which is disposed between and slightly above these arms.The shaft 65 is rotatably mounted and adapted to be driven from aninternal combustion engine in proper timed relation therewith. In thisparticular case, it is adapted to be driven at crankshaft speed from afour cylinder, four cycle engine. The shaft near one end has a bearingof ample diameter and length in the end frame 61 (Fig. 6), and near itsother end has a hearing in the post 59. A collar 66, fixed to shaft 65,engages the outer end face of the first named hearing and serves to takeany inward end thrust occasioned by the coupling (not shown) by means ofwhich shaft is connected to the engine. The shaft extends beyond post 59and carries a cam 67 to actuate the distributer arm 34, hereinbeforereferred to. The shaft 65 is provided with two cams 68 and 68 foroperating the hinge arms 56 and 56 respectively. These cams arepreferably made up of steel laminations, as indicated in'Figs. 6 and 10,because a certain degree of desirable resiliency is obtained thereby andbecause of economy in construction. The laminated construct-ion of thecams also helps, in so far as lubrication is concerned, because oil willbe held between the laminations and will more readily cling thereto thanto the smooth periphery of a solid cam. The shaft 65 is, forconvenience, made in three sections as shown in Fig. 10, the sections aand I) being joined by a sleeve section 0, in which the other sectionsare secured by a drive fit. The laminations are clamped between a flangeon section a and one end of sleeve 0. These cams are alike but arrangedin diametrically opposed relation on shaft 65 Fig. 4). They are alsospaced one from the other longitudinally on this shaft, although bothare arranged in close proximity and in close proximity to-elid frame 61(see Fig. Each cam has adwell portion d of substantial angular extent.In the example shown, the dwell portion- "'tis approximately 140 degreesin angular ex-, tent. The remaining portion of the peripl i,;.

cry of each cam is made up of a rise portion 0 and a drop portion f',the sc two portions gradually merging together and-each graduallymerging with the dwell portion d. The cam construction will be laterconsidered in further detail but for the present it will suffice tostate that the active portions of cams 68 and 68 are opposed --sotliat,.while one cam is functioning to move its armature away from itspoles, the other cam permits the other armature to move backtoward andinto contact with its poles. ,...The armatures 20 and 20' thus wort:substantially in alternation although not in exact alternation.

The armatures may be moved in their flights away from their poles ineither of two ways. First, they may be moved entirely by an inelastictransmission of force from their cams 68 and 68. Second, they may beinitially moved a very short distance away from their oles in thismanner (to pry the armatures loose from their poles and break themagnetic hold) and thereafter be moved the remaining distance by theexpansive action of previously stressed elastic means.

The inelastic transmission is effected by the following mechanism. Alever 69 (Figs. 4 and 7) is mounted intermediate its ends to turn freelyon the cylindrical end 63 of the armature hinge arm 56. A cam follower,comprising an arcuate flange 70 bent out wardly at right angles from thefree end of an S-shaped arm 71 of metal plate, is interposed between oneend of lever 69 and its cam 68. The follower arm 71 is pivotally mountedon a stud 73 (Figs. 4 and 7) secured to a lug 74: on frame 61. In thecase of the follower 71, the pivot stud 73 is secured to a post 75,which depends from frame 18 (Fig. 7). The lever 69, at its. other end,is provided with an adjustable abutment in the shape of a screw 76 (Fig.4), designed to bear against the lower end of a pin 77, which is mountedto slide freely in av rig-78 formed on frame 18. An armature returnspring 72, (Fig. 1) interposed between armature 20 and base plate 60tends to hold the armature to its poles and thus tends to raise thehinge arm 56 and the lever 69 carried thereby, whereby the lever 69 islifted, one end being caused to bear on pin 77 and the other end beingcaused to bear on follower 70, thereby urging the latter toward its cam68.

The pin 77 may be held against upward movement, beyond the illustratedposition or, by adjustments to be described, it may be held againstupward movement beyond tain other and higher vertical positions. Whenthis pin 77 'is held from moving upwardly beyond the illustratedposition, a

direct or inelastic drive of the armature 20 ""from cam 68 results.Thus,,the pin 77 forms a fulcrum for lever 69 and, as the free end ofthe latter is depressed by cam 68, the hinge arm 56 is lowered andarmature 20 is pried off its poles, to which it was theretoforc held bythe strong force of magnetic attraction. and moved away from its polesthe required distance.

In order to hold the fulcrum pin 7 7 against upward movement beyond theillustrated po-- sition, or beyond various other and higher verticalpositions, a cam 79 is arranged to bear on the upper end of pin 77, asshown in Figs. 1 and 4. This cam and the cone spending cam 79 are fixedto a shaft 80 near opposite ends thereof. This shaft, which (BX- tendstransversely across frame 18', is seated in semi-circular bearingsformed in the upper ends of the described posts 43 and located forwardlyof cross bar 41. It is held in each of these hearings by a strap 81, oneend of which underlies the cross bar 41 (Fig. 6) and is upturned to bearagainst the same as a fulcrum. The strap 81 passes across the top ofshaft 80 and-its other end is drawn down- It will be noted that the cams79 may be turned throughout a certain range (through the angle as shownin Fig. 9) without permitting a change in the vertical position of thefulcrum pins 77 and 77. If moved beyond this range, the cams will permitthese pins to be raised. to various higher positions.

When the cams are positioned to permit thelast mentioned condition, themovement of the armatures away from their poles, after the preliminaryprying off of the armatures by the inelastic transmission of forcedescribed, is effected by the expansive action of previously stressedelastic means. To secure this action, a drive spring 84 is interposedbetween a rearwardly offset lug 85 on lever 69 and an abutment 86,adjustably secured to cross bar 41 (Figs. 1 and 5). The abutment 86 hasa long depending guide 87 extending into the spring to restrain it fromundue transverse flexure and the abutment 85 has a projection 88entering the lower end of the spring. It will be seen that, if pin 77 isfree to rise above the illustrated position, the first action followingthe depression of cam follower by cam 68 will be to tilt lever 69 aboutthe cylindrical end 63 of the armature hinge arm as a fulcrum. Thisfollows be-.

cause the armature is held firmly to its poles by magnetic attractionand because the pin 77 is free to rise. Thus, the outer end of lever 69is raised and the drive spring 8i is thereby placed under stress. Thisdrive spring, even when stressed as much as possible with theillustrated arrangement,is insufficient to over come the force ofmagnetic attraction which holds the armature to its poles. Consequently,the stressing of the drive spring continues until the pin 77 is arrestedin its upward movement by cam 79. Then pin 77 functions as before as afulcrum for the lever 69 and the armature is pried off its poles by thedescribed inelastic transmission of force from cam 68. Immediatelyfollowing the prying oil' of armature 2O from its poles. the magneticattraction'on the armature 1s so diminished by the creation of even avery small air gap betweeuthe armature and its poles, that thepreviously stressed drive spring 84. is enabled tomove the armature andmore rapidly than it would be moved by cam- 68. Consequently, spring 84expands and, since the inner end of lever 69 bears on cam 68, the lattertemporarily serves as a fulcrum therefor, while the lever and thus thearmature 20 is being moved by the expanding drive spring.

It will be obvious that the degree of stress ing of the drive spring maybe varied according to the position of pin 77, being greater if the inis allowed to rise higher. It will also be 0 vious that the time whenthe armature leaves its poles with relation to the angular position ofshaft 65 may be varied by the setting of pin 77. When the latter ispositioned as illustrated, the armature leaves its poles at an earlierposition in the revolution of shaft 65, or in what may be termed fulladvance position. If, however, the cams 79 be so set as to allow thepins 7 9.to rise above the illustrated position, the armature leaves itsoles at a later time in the revolution of sha't 65, or in what may betermed retard v position. The production of a spark from- Y the magnetodepends on the tinie of separation of the breaker points 25 and 26 andsuch separation is effected by the movement of armature 20 and normallyoccurs after the armature has moved a certain distance away from itspoles. Consequently, with the described arrangement, a retarded spark isproduced from the magneto when spring drive.

is used and 'this is the desired condition for the spring drive isintended to be used primaril when the engine is started. B the use 0other means, later to be describe the point in the downward flight ofthe armature at which the breaker points open ma be varied'so that it ispossible, should such a condition be desired to arran e for advancedspark when spring drive 0 the armature is used.

The mechanism for separating the breaker points 25 and 26 will now bedescribed with particular reference to Figs. 5,6 and 7. The plates 57and 57 heretofore described as fixed to the armatures'20 and 20', extendbeyond their armatures (to the left as viewed in Figs. 6 and 7) and thefree end of each is given a quarter turn, thereby forming a horizontallydisposed lug 90. Passing freely through the lugs 90 and 90, as bestshown in Fig. 5, are screws 91 and 91' which are disposed on oppositesides of shaft 65. These screws also pass freely through a lever 92, onenear each end thereof, and are supported from the lever by their headswhich rest on crimped portions of the lever. This lever 92 encompassesthe described stem 51 and cen-- trally betweenits ends is fulcrumed onthe upper face of flange 52. The lever 92 is crimped at its middle toafford substantially lock nuts 94 and 94 to hold the abutments in theiradjusted positions.

The arrangement described permits the one interrupter to be operatedalternately by the two armatures. As armature 20' left 5 all slack inthe connections is taken up its poles to reach the illustrated positionthe lug 90 eventually came into engagement with abutment 93' and tiltedone end of lever 92 downwardly about its central crimped portion as afulcrum, thus raising the other arate breaker point 25.from breakerpoint 26.

The raised end of lever 92then served as a fulcrum, bearing on the headof screw 91. The arrangement is such that the points 25 and 26 areseparated at an intermediate point in the flight of armature 20' awayfrom its poles. As armature 20' moves back toward its poles,.the spring53 causes the points 25 and 26 to be again engaged and just as thearmature 20 is about to seat on its poles 12', the armature 20 starts toleave its poles 12. The armature 20, in its flight away from its poles,causes lug 90 to engage abutment 93 and tilt the righthand end oflever92 (Fig.

downwardly, raising the other end unti an thereb depressing flange 52,with the raised end 0 lever 92 bearing as a fulcrum on the head of screw91'. Thus, the armature 20 also serves to separate the breaker points atan intermediate point in its downward movement. By suita le adjustmentof the parts, the breaker points are caused to separate at the optimumpoint in the downward flight of each armature.

It has been shown heretofore wherein a change in the timing of thesparks from the magneto may be effected by changing the positions ofcams 79 and 79', whereby the armature is caused to leave its oles atlater times when spring drive is use for the armature than when thelatter is directly driven. It is often desirable to vary the timing whendirect drive is used for the armature and for such purpose means areprovided for varying the vertical position of the up or breaker point26. Such means are pre erably controlled from shaft 80 and, as shown inFigs.

4 and 6, a cam 95 is formed integrally with and on the central portionof shaft 80. Cam 95 is adapted to engage a rocker arm 96 pivotallymounted on a pin 97. Pin 97 is secured at its ends in laterally spaceddepending ears formed on a washer like piece 98 which is held in placebetween the lower face of cross bar 41 and the flange of the describedbushing 45. The inner end of rocker arm 96 straddles the interruptercasing 46 and bears against the flange 48. Consequently, when arm 83 isso turned as to cause cam 95 to lift the outer end of rocker arm 96, theinner end thereof forces flange 48 downwardly and causes breaker point26' to be lowered. The lowering of point 26 naturally causes a laterdisengagement of point 25 therefrom. As I of the fulcrum pins 77.Therefore, the spark can be advanced or, retarded while the cams 7 9and79, are set for direct drive of the ar- .mature, these cams having dwellportions Corresponding in angular extent to that necessary to move cam95 to cause a lowering of breaker. point 26 throughout its entire rangeof movement. This range is sufficient to give all the'spark control thatis desired, from full advance to full retard and is designed to providefor a retarded spark which is at least as late as that obtained whenspring drive is used.

When shaft 80 is turned from the position 6 shown in Fig. 1 throughoutthe angle w (designated in Fig. 9) the upper breaker point 26 is movedfrom its highest vertical position downwardly as far as possible. Ofcourse, this range of movement can readily be changedin degree and couldeven be reat enough to prevent any separation o the breaker points bythe armatures if that condition should be desired for any reason. If theshaft 80 is moved counterclockwise, as viewed in Fig. 9, back throughthe angle a: the upper breaker point 26 is restored to its originalposition, which is such as to. cause the separation of the breakerpoints to occur at the optimum point in the downward flight of eacharmature. This optimum point for direct drive of the armature is in thiscase slightly different from the optimum point when the armature ismoved by spring drive. Accordingly, the cam 95 is so constructed as toproperly position the upper breaker point 26 to permit separation of thebreaker points at a slightly different point in the downward flights ofthe armatures when the latter are moved by the spring drive. When cam 79has been turned clockwise from the position shown in Fig. 1, through theangle :21, the

highest point of the cam 95 bears on the rounded left hand end of therocker arm and provides the full retarded spark for direct drive of thearmature. If, now, the spring drive is to be used, the shaft 80 isturned still further in a clockwise direction into a position such asshown in Fig. 9, or still further 1 one side of the cam is wider thanthe other be produced arm 96 from rising so far as it could if cam 79was positioned as shown in Fig. 1. Thus, the maximum vertical positionof breaker point '26 is different when spring drive is used than whendirect drive is used. The difference is not very great but it isnevertheless very important because it allows the spark to at the mostfavorable point in the downward flights of the armatures with each formof drive. Except for the arrangement described, the separation of thebreaker points would have to occur at the samepo-int in the downwardflight of each armature, re-

gardless of which form of drive is used, say

at some point which is a compromise between the point which is mostfavorable when spring drive is used and the point which is mostfavorable when direct drive is used. The described arrangement avoidsany such comprise and permits the best results to be obtained with eachform of drive.

The general operation of the magneto-will pow be described. As shaft 65is revolved 'rst one and then the other armature is moved. Each armaturemoves through one cycle, that is, away from its poles and subsequentlyback into contact therewith, during a little more than a half revolutionof shaft 65 and dwells on its poles during the remainder of saidrevolution. These cycles occur in alternation so that two sparks areproduced during each revolution of shaft 65 at symmetrical intervals.Thus, the magneto, when shaft 65 is driven at crankshaft speed, willproduce the ignition sparks necessary for a four cylinder, four cycleengine,the ignition E. M. F. from the magneto being distributed atproper intervals successively to the several cylinders by thedistributer D, as above described. As one armature, say 20% moves awayfrom its poles, the reluctance o itsmagnetic circuit is greatlyincreased and when the breaker points 25 and 26 separate, the chokingwinding 21, which has theretos fore tended to restrain a change of flux,is opened and a sudden change of flux results thereby generating an F.in coils 22-. As the other armature 20 moved toward and into contactwith its poles (such contact occurring with either drive shortly afterarmature 20 has left its poles), the reluctance of the magnetic circuitof which armature '20 is a part was also changed although a flux changewas, to a large extent, restrained because the choke windings 21' wereshort circuited during the latter part of the return travel ofarmature20. The separation of breaker points 25 and 26 serves, as will be seenfrom Fig. 8, to open both the choking windings 21 and 21 so that twoflux changes, one due'to the downward movement of armature 20 and theother due to the upward movement of armature 20, are produced and, byreason of the common control through the one set of breaker points,these two flux. changes-are. made to simultaneously produce two E. M. vF.s,-one in windings 22 and the other in windings 22. These generatingwindings are interconnected, as described, so that the two E. M. F.s aremerged. As shown, they are added so that a better spark is produced bythe two cooperating units than could be obtained with either whenworking separately.

Considering the armature actuating mechanism in more retail andreferring to it also in connection with Fig. 11, it will be noted thatthe rise portion 0 of cam 68 is peculiarly formed. It starts with a slowgradual rise, indicated by the are 9 and is followed by a quick sharprise it. Near the endof the rise portion 6 is a part '5, over eachincrement of which the rate of change of rise is constant.

While there is a continuous rise over the entire angular extent ofportion 6, the rate of change for equal angular increments varies.Throughout the angle g, the rate of change is small but graduallyincreasing. This c0nstruction enables the armature to be removed slowlyfrom its poles. Consequently, this heavy duty work is accomplishedwithout a shock or blow. WVith direct drive the arma ture starts toleave its poles when the cam follower rides onto the very beginning ofthe initial portion 9 of the rise e and it is accelerated, at first bysmall increments and then by very much larger increments, so that thecam follower begins to acquire appreciable speed as it rides onto theart h. By reason of the part h, the cam fo lower is accelerated stillmore rapidly and the armature then acquires what may be called trispeed. That is, it gets to moving rapidly enough so that the speedcondition is favorable for opening the breaker points. This speed isacquired at a time when the arm-a ture is separated an appreciabledistance from its poles so that the air gap condition is likewisefavorable for opening the breaker points and suchaction then ensues.With direct drive, the breaker points open at. about the time when thecam follower has reached the end of the part it of rise 6. The spark,having been produced by the opening of the 1 breaker points, furtherdownward movement of the armature by cam 68 does not affect theelectrical o eration of the magneto and the cam can an does continue tolower the armature still further,-finally permitting it to-return to itspoles under the action of spring 72. Thefinal part of dwell portion f isso fashioned as to cause the armature to slow drive spring and thearmature is not moved until the cam follower rides onto the portion 2'of the cam. This portion, as described. has a constant rate of rise forequal angular increments so that the tripping of the armature, althoughvaried by the adjustments de scribed so as to occur at different pointsover the range of portion 1' will always occur under similar conditions.The movement of the armature under the action of the drive spring 84 isexceedingly rapid but there is some lag even in such a rapidly operatingmember and, on this account, the rise of the cam is continued beyond thelatest point at which the spring action can be initiated. This extensionof the rise (that portion between the portions '5 and is provided forinsurance. It positively prevents the armature from moving back'untilthe drive spring has moved the armature far enough to cause a separationof the breaker points. In other vwords, the cam follows along behind thespring for a certain time and insures against any possible trouble fromthe source mentioned.

The return spring 72 need not necessarily be arranged to move thearmature all the way back into contact with its poles. It will sufiiceif the return spring moves the armature far enough back toward its polesso that it can be drawn into contact therewith .by magnetic attraction.Also, it is possible to eliminate the return spring and rely entirely onthe breaker point spring, which tends of course to lift each armature.

A novel and important feature of this invention consists in theprovision of means for arresting each armaturein its return flighttoward its poles and preventing the same from contacting with such poleswhile the other armature is in contact with its poles. The provision ofsuch means is useful and important when the armatures are being operatedby spring drive. Such means is not necessary and does not function whenthe armatures are being operated. by direct drive.

' By reference to Fig. 11, it will be seen that when one cam follower,as 70, is riding on dwell portion d of its cam 68, (the conditionnecessary to permit armature 20 to contact with its poles) the other camfollower 7 0- will be riding on a diametrically opposed part of its cam68 and thus on either the rise portion 6 or the fall portion f.Consequently, with direct drive. both armatures cannot be in contactwith their respective poles at the same time. When, however, thearmatures are being operated b spring drive, it would be possible,except or the provision of the means above referred to, for botharmatures to be in contact with their respective poles at the same time.Recalling that with spring drive, one armature, as 20, does not leaveits poles until its cam follower 70 reaches the part i of its cam 68, itwillbe apparent from.

Fig. 11 that the other cam follower 70 will then be ridin on thediametrically opposed portion, viz, tie dwell portion (Z of cam'68,whereby the annature 20 would, unless prevented by splecial means, he incontact with its poles. vcn with a condition of this kind, the magnetowill operate satisfactorily enough for a great many classes of servicebut, bearing in mind that the magneto of this invention is intended foruse on tractors, which have to be started by cranking and often in verycold weather, it. becomes most important to provide for the productionof the best pos sible spark for use in starting under these severeconditions. I have found that the'operation of the magneto under springdrive is very greatly improved and that a longer and fatter sparkresults if one armature on its upthrow stroke is held away from itspoles until the other armature starts to leave its poles. The desiredresult is to reproduce with spring drive operation the same generalconditions as obtain with the direct drive operation, ashereinbefore-described.

The particular expedient illustrated for accomplishing the desiredobject consists of a cross bar 101 which, as best shown in Fig. 12, issupported at opposite ends by resting on the top edges of the armaturehinge arms 56 and 56 and extends across from one to the other, passingbeneatlrthe drive shaft 65. As will be apparent from Fig. 12, when thearmature 20 moves upwardly toward its poles it will raise the left handend of bar 101 until the latter engages the drive shaft 65'(or any othersuitable abutment for that matter) and thus arrest the armature 20 untilarmature 20 is moved out' of contact with its poles. The particularexpedient shown has been chosen primarilyasa simple way of illustratingthe essential idea. This expedient is doubtless capable of refinementand various other expedients, differing in detail from that shown, willdoubtless occur to those skilled in the art. The details are not nearlyso important as theresult pointed out herein. I point out, however, thatit is desirable to keep the cross bar inplace both laterally .andlongitudinally on the hinge arms 56 and The disadvantage in allowingboth a-rma tures to contact with their poles at the same time is thatone tends to shunt some of the magnetic flux from the other. In Fig.'12, armature 20, which has been dwelling on its urpose of allowing fluxto build netic circuit of which it'is a. 1, especially in very low speedrobbed of some flux if the armaie into contact with its poles bee hadmoved away from its niountered because the time eleindings will rcuitsover short intervals. The 'ntcrval, however, the less effective nginfluence of the choke windequently, although the breaker gaged and thechoke windings ed, when armature 20 apely to its poles, this armaturesieving relatively slowly, as at ls, rod flux from the Other aroat is mytheory of the action. s have proved by experiment, b longer and fatterspark can th spring drive operation of -s magneto when the cross bar 101is used a 'thout it. The result is most imporg a large, fat spark forinsurnition at cranking speeds even old weather.

ower 70 and its integral supsequence. Such, however, is hese elementsare important .y save the armature hinge arm y lateral strains to whichit we be subjected. As the cam d commences to depress the also exerts alateral thrust this case is transmitted 71 to the stud 73, secured toune. In this way, the burden '"zirust is taken by the cam folthe desireddownward mo- .-icated to lever 69. This is because the armature hinge Ia point remote from that is located. Consequently, a E ermitted on lever69, would through arm 56 as a long art considerable strain thereon. earm 56 would, by reason of e free to move sidewise to some e lateralthrust and such conesired. 76 also has its importance. It the up allslack in those parts of actuating mechanism which the armature is drivensolely The motive is to keep all ct and avoid all noise-producentsduring normal operation 0. It is contemplated that the be operated forthe most part e,-the spring drive usually beparticularly for starting.The

wi l

so 1 a speed op eration,less difiiculty ll may, at first glance, appearto small force applied at the drive shaft.

magneto operation under direct drive. The

slack in the driving connections is taken up as follows ;eam 79 is firstmoved into proper position for direct drive and then screw 76 is turneduntil pin 77 has been raised into contact with cam 79, after which thescrew is turned still further until lever 69 is engaged with camfollower 70 and the latter is moved into contact with cam 68. This screwcan also be utilized for another purpose, viz, to prevent contact of thearmature with its poles, if and when desired. If the screw be turnedstill further in the same direction after all the slack in the operatingconnections has been taken up, the armature can be removed from itspoles. In this way, the upward movement of the armature, when operatedby direct drive, can be limited so that contact between it and its polesis prevented. A very slight air gap may thus be created, instead of acondition of actual contact, between the armature and its poles.

By the particular armature mounting chosen, wherein the hinge armextends longitudinally rather than crosswise of the armature, a powerfulleverage is available. A longer hinge arm can be used than would befeasible if the arm extended crosswise of the armature because spacelimitations are such that more length than width is available. Thefulcrum of the hinge arm can be-located beyond one end of the armatureand just far enough beyond this end to admit of sufiicient separationbetween the armature and the ad jacent core] The force is applied to thefree extremity of the hinge arm at a point well beyond the opposite endof the armature, so that such force removing the armature from itscores. The lever 69, by means of which the actuating force is applied tothe free end of hinge arm 56, also serves to multiply the force appliedto it, whether that force is applied by the cam 68 or by the drivespring 84:. In either case, the force is applied to one end of the leverand the fulcrum of the lever is at the opposite end, while the load is,as shown, in the center. The force applied to lever 69 is thereforedoubled (and it might be still further increased if necessary ordesired) when applied to hinge arm 56. Consequently, a system ofmultiplying levers is-available for the purpose of performing the heavyduty of prying the armature off its poles with a relatively t followsthat the latter can be turned with comparative ease, even by hand. Italso follows that if the shaft can be easily turned in this manner thatthere is an absence of severe blows and shocks in operation. The underling reasons for this have been explained above in connection with theconstruction of cam 68. It need onlybe' stated is multiplied for thework of i here that the magneto operates with surprising quietness evenat high speeds, such as those above referred to, and this is a newaccomplishment in a magneto of the reciprocating and contacting armaturetype.

Another important feature relates to the disposition and relativearrangement of parts of the armature actuating mechanism. Thearrangement disclosed is characterized by compactness and theeflicientutilization of substantially all available space between thebase and the plate-like member 18. i The [arrangement likewise permits,in a magneto having two armatures, the grouping of the two drives at oneend of the machine. Both cams 68 can be located close to the large mainbearing in the end frame 61 and only a small part of the shaft, asshown, need be of large diameter. The remainder of shaft 65 is notsubjected to any material torsional strain because it simply serves todrive the distributer arnr 34. The shaft is not extended beyond cams 68and 68 solely for this pur ose, however. Where. as here, it is noteasible'to get an ample bearing on each side of the cams, and closelyadjacent thereto, the condition imposed is that of using cranksoverhanging from one bearing. This conditionnormally is poor but by theuse of a long extension of the shaft, supported as shown at a pointremote from the cranks, a long leverage is ob tained to prevent lateraldeflection of the shaft in its main hearing. A smaller main bearing canbe used than would otherwise be the case and the bearing is saved frommuch of the wear to which it would otherwise be subjected.

To meet existing standards recognized in the trade, such as those set,for example, by the Society of Automotive Engineers, it is necessary tokeep the height and width of the magneto within certain limits. It isalso necessary that the center of the drive shaft be located a fixeddistance from the bottom of baseGO. The present magneto meets thesestandards and largely because of the disposition and relativearrangement of parts of the armature actuating mechanism. To keep downthe height of the magneto, the space between the frame members 18 and 60has been reduced to a minimum. The space shown is thatnecessary for thearmature movement plus some additional space for an adequate returnspring. It will be noted that spring 72 has been let into base 60, asfar as is feasible to'save vertical space. There is not room above orbelow the armatures for driving mechanism or any substantial partthereof. Consequently, the armature hinge arm has been fixed to one sideface of the armature and extends beyond one end thereof for connectionto other parts of the mechanism. The cams, the centers of which must, tosatisfy existing standards, be fixed in height, are located beyond saidend of the armature where vertical height is available. With the twounit machine, the distance between the cores 12 and 12' is the limitingcondition so far as width is concerned. These have been placed asclosely together as possible. This results in a certain free spacebetween the armatures and such space has been substantiallly filled, aswill be evident from Fig. 7 by the drive shaft, the armature hinge arms,and the operating arms 57 and 57 for the interrupter.

The particular relative arrangement of parts is thus important in thatit not only enables a desirable system of multiplying levers to be used,whereby but a small force is required at the drive shaft for operationof the magneto, but it is also important for the reason that it enablescertain arbitrary standards set by the automotive industry to be met bya reciprocating armature type of magneto, whereby the latter type isrendered suitable in one respect for a new field of service. In anotherand most important respect, the magneto is rendered suitable for thisnew field of service by reason of the improved actuating mechanism whichadmits of commercially satisfactory operation at the high speedsrequired and at speeds much higher than those heretofore attempted witha magneto of this type.

The invention has been disclosed herein, in an embodiment at presentpreferred, for illustrative purposes but the scope of the invention isdefined by the appended claims rather than by the foregomg description.

What I claim is:

1.;In a magneto, of the type wherein an armature is moved into and outof contact with its pole pieces and wherein the flight of the armatureaway from its pole pieces is initiated by a pryingoff of the armature byan inelastic transmission of force thereto, mechanism for prying thearmature off its pole pieces, comprising, a lever extending generallycrosswise with respect to the armature, a pivotal support for said leverengaging the latter intermediate its ends and rigidly connected to thearmature to move with the'same, inelastic means for transmitting to onepart of said lever a driving force and a member for engagement withanother part of said lever and serving as a fulcrum therefor.

2. In a magneto, of the type wherein an armature is moved into and outof contact with its pole pieces and wherein the flight of the armatureaway from its pole pieces is initiated by a prying off of the armatureby an inelastic transmission of force thereto, mechanism for prying thearmature off its pole pieces, comprising, a lever extending generallycrosswise with respect to the armature, a pivotal support for said leverengaging the latter intermediate its ends and rigidly consame, inelasticmeans for transmitting to one part of said lever a driving force, afulcrum member disposed in the path of another part of said lever, andmeans whereby the position of said fulcrum member may be varied to varythe time at which the lever is effective to pry the armature off itspole pieces.

'3. In a magneto, of the type wherein an armature is moved into and outof contact ith its pole pieces and wherein the flight of the armatureaway from its pole pieces is initiated by a prying off of the armatureby an inelastic transmission of force thereto, mechanism for prying thearmature off its pole pieces, comprising, a lever extending generallycrosswise with respect to the armature and having a pivotal bearingcarried by movable with the same, inelastic means transmitting to onepart of said lever a driving force, a fulcrum member disposed in thepath of another part of said lever, means whereby the position of saidfulcrum member may be varied to .vary the time at the lever is effectiveto pry the armature off its pole pieces, and resilient means engagingsaid lever and capable of being stressed by movement of said leverpreliminary to the prying off of said armature and efiective thereafterto move said lever and c to complete the flight of the latter away i itspole ieces. I

4. T i a magneto, of the type wherein an armature is moved into-and outof contact with pole pieces and wherein the flight of the mature'awayfrom its ole pieces is initiated by s prying off of tie armature by anremission of force thereto, mechrying the armature 01f its polemechanism comprising, a lever generally crosswise with respect to r andhaving a pivotal bearing i movable with the same, in-

driving force, a fulcrum member i the path of another part of said hewhereby the position of said ful- Th9? may be varied to vary the time helever is efiective to pry the armapole pieces, and resilient means aidlever and capable ofbeing iy movement of said lever prelimihe pryingoif'of said armature and er ctive thereafter to move said lever andarms'ure complete the flight of the latter sway om pole pieces, saidfulcrum membeing movable to a position wherein said is ineffective tocause movearmature. magneto, of the type wherein an ure is moved intoand out of contact ole pieces and wherein the flight of more away fromits pole pieces is d by a prying off of the armature by transmission offorce thereto,

' its mechanism for prying the armature ofi its pole pieces, saidmechanism comprising, a lever extending lengthwise of the armature andconnected thereto for moving the same and extending beyond opposite endsthereof, a pivotal support for said lever located beond one end of thearmature, a second lever pivoted to the first lever and extendingsubstantially crosswise thereof at a point beyond the other end of thearmature, inelastic means for transmitting a driving force to one partof said second lever, and a fulcrum member disposed in the path ofanother part of said second lever.

6. In a magneto, of the type wherein an armature is moved into and outof contact with its pole pieces and wherein the flight of the armatureaway from its pole pieces is initiated by a prying off'of the armatureby an inelastic transmission of force thereto, mechanism for prying thearmature off its pole pieces, said mechanism comprising, a leverextending lengthwise of'the armature and connected thereto for movingthe same and extending beyond each end thereof, a pivotal support forsaid lever located beyond one end of the armature, a second leverpivoted to the first lever and extending substantially cross-wisethereof at a point be yond the opposite end of the armature, inelasticmeans for transmitting a driving force to one part of said second lever,a fulcrum member disposed in the path of another part of said secondlever, and means whereby the position of said fulcrum member may bevaried to va the time at which said secondlever is effective to pry thearmature off its pole pieces.

7. In a magneto, of the type wherein an armature is moved into and outof contact with its pole pieces and wherein the flight of the armatureaway from its pole pieces is initiated by a prying off of the armatureby an inelastic transmission of force thereto, mechanism for prying thearmature off its pole pieces, said mechanism comprising, a leverextending lengthwise of the armature and connected thereto for movingthe same and extending beyond each end thereof, a pivotal support forsaid lever located beyond one end of the armature, a second leverpivoted to the first lever and extending substantially crosswise thereofat a point beyond the opposite end of the armature, inelastic means fortransmitting a driving force to one part of said sec ond lever, afulcrum member disposed in the path of another part of said secondlever, means whereby the position of said fulcrum member may e varied tovary the time at which said second lever is effective to pry thearmature ofi its ole pieces, and resilient means capable of eingstressed by said second lever preliminary to the prying off of saidarmature and effective thereafter to move oft the second lever and thusthe armature to complete the flight of the latter away from its oles. 1P 8. In a magneto, of the type wherein an armature is moved into and outof contact with its pole pieces and wherein the flight of the armatureaway from its pole pieces is initiated by a prying off of the armatureby an inelastic transmission of force thereto, mechanism for prying thearmature off its pole, pieces, said mechanism comprising, a leverextending lengthwise of the armature and connected thereto for movingthe same and extending beyond each end thereof, a pivotal support forsaid lever located beyond one end first lever and extendingsubstantially crosswise thereof at a point beyond the opposite end ofthe armature, inelastic means for transmitting a driving force to onepart of said second lever, a fulcrum member disposed in the path ofanother part of said second lever, means whereby the position of saidfulcrum member may be varied to vary the time at which said sec- 0ndlever is effective to pry the armature off its pole pieces, andresilient means capable of being stressed by said second leverpreliminary to the prying off of said armature and effective thereafterto move the second lever and thus the armature to complete the flight ofthe latter away from its poles, said fulcrum member being movable to aposition such that said resilient means is rendered ineffective to causemovement of the armature.

9, In a magneto, of the type'wherein an armature is moved into and outof contact with magnetic pole pieces, a lever, a pivotal supporttherefor carried by said armature, means for applying a driving force tosaid lever to turn the same on said support as a fulcrum, and means inthe path of said lever efi'ective to arrest the lever and temporarilyserve as a fulcrum therefor, thereby to enable the lever to pry thearmature off its pole ieces.

10. In a magneto, of the type w erein an armature is moved into and outof contact with magnetic pole pieces, a pivotal support carrie by saidarmature, a lever mounted to turn on said support and extending in adirection generally transverse with respect to the armature, meanstlt'er applying a driving force to said lever to turn the same on saidsupport as a fulcrum, and means in the path of said lever effective toarrest the lever and tem porarily serve as a fulcrum therefor, therebyto enable the lever to pry the armature off its pole pieces.

11. In a magneto, of the type wherein an armature is moved into andoutvof contact with magnetic pole pieces, a lever, a pivotal support forthe lever carried b the armature, a drive shaft, means operable by thelatter to effect an inelastic transmission of force to said lever,resilient means capable of being stressed e armature, a second leverpivoted to the by said lever when the latter is moved by said driveshaft, and stationary but adjustable means disposed in the ath of saidlever and serving as a fulcrum t erefor to enable the armature to bepried off its pole pieces by said lever when moved by said inelastictransmission of force, said means bein adjustable to a position whereinstressing of said means by movement of said lever is prevented or to aposition wherein such stressing is permitted.

12. In a magneto, of the type wherein an armature is moved into and outof contact with magnetic pole pieces, a lever connected to the armaturefor moving the same and pivotally supported at a point beyond one end ofthe armature, said lever extending beyond the other end of the armatureand terminating with a pivotal support, a second lever mounted to turnon said pivotal support, means for applying a driving force to saidsecond lever to turn the same on said support as a fulcrum, and means inthe path of said second lever effective when engaged thereby to arrestthe second lever and temporarily serve as a fulcrum therefor, thereby toenable the second lever to pry the armature off its pole pieces.

13. In a magneto, of the type wherein an armature is moved into and outof contact with magnetic pole pieces, a pivotal support carried by thearmature, a lever mounted in termediate its ends to turn on saidsupport, driving means engageable with said lever on one side of saidsupport for moving the same by an inelastic transmission of force,resilient means engageable with said lever on the opposite side of saidsupport, and limiting means in the path of the last named side of saidlever to engage the same after said resilient means has been stressedand to temporarily serve as a fulcrum to enable the armature to be priedoil said pole pieces by said inelastic transmission, said stressedresilient means effective after the armature has been pried off its polepieces to move the lever and complete the flight of the armature awayfrom its pole pieces, the part of said driving means engaged with saidlever serving as a fulcrum therefor when the lever is moved by saidresilient means. I

14. In a magneto, of the type wherein an armature is moved into and outof contact with magnetic pole pieces, a pivotal support carried by thearmature, a lever mounted intermediate its ends to turn on said support,driving means engageable with said lever on one side of said support formoving the same by an inelastic transmission of force, resilient meansengageable with said lever on the opposite side of said support, andlimiting means in the path of the last named side of said lever toengage the same after said resilient means has been stressed and term dafter the armature has been'moved out of silient means effective afterthe armature has been pried off its pole pieces to move the lever andcomplete the flight of the armature away from its pole pieces, the partof said driving means engaged with said lever serving as a fulcrumtherefor when the lever is moved by said resilient means, said limitingmeans being movable to a position such that stressing of said resilientmeans by said lever is prevented, whereby the flight of the armatureaway from its pole pieces may be effected entirely by said inelastictransmission of force.

15. In a magneto of the type wherein an armature is moved into and outof contact with magnetic pole pieces, a pivotal support carried by thearmature, a lever mounted to turn on said support, driving means foreffecting an inelastic transmission of force to said lever at onelocation, resilient means for effecting, an elastic transmission offorce to said lever at another location, and a member serving as afulcrum for the lever to enable the lattertobe movedb saidinelastictransmission of force to move t e armature out of contact with its olepieces, said member being movable to ifl'erent positions, in one ofwhich said resilient means is rendered ineffective to move said leverand in others of which the le. ver, when first moved by said drivingmeans turns on said pivotal support as a fulcrum and effects a stressingof said resilient means before engagement with said member, wherebycontact with its pole pieces said resilient means in relieving itself ofstress moves said lever about the part of driving means engagedtherewith as a fulcrum and thereby moves said armature.

16. In a magneto, of the type wherein an armature is moved into and outof contact with magnetic pole pieces, mechanism for moving the armatureaway from its pole pieces, comprising, a pivotal support carried by thearmature, a lever mounted at a point intermediate its ends to turn onsaid support and extending in a direction generally transverse withrespect to the armature, a drive shaft, a cam operated thereby andtransmitting a force to one end of said lever, whereby the latter turnson said support as a fulcrum,

resilient means engaging the other end of thelever and stressed by thedescribed movement, a member in the path of said last named end of thelever and engageable thereby to limit the stressing of said resilientmeans, said member when first engaged by the lever serving as a fulcrumtherefor to enable the armature to be pried off its pole pieces by themovement of the lever effected by said cam, the cam then servin as afulcrum for the lever while the latter is moved by said previouslystressed elastic means.

17 In a magneto, of the type wherein an armature is moved into and outof contact with magnetic pole pieces, mechanism for moving the armatureawa from its pole pieces, comprising, a pivota support carried y thearmature, a lever mounted at a point intermediate its ends to turn onsaid support. and extending in a direction generally transverse withrespect to the armature, a drive shaft, a cam operated thereb andtransmitting a force to one end of sai lever, whereby the latter turnson said support as a fulcrum resilient means engaging the other end 0thelever and stressed by the described movement, a member in the path ofsaid last named end of the lever and engageable thereby to limit thestressingof said resilient means, said member when first engaged by thelever serving as a fulcrum therefor'to enable the armature to be priedoff its pole ieces by the movement of the lever effected y said cam, thecam then serving as a fulcrum for the lever while the latter is moved bysaid previously stressed elastic means, said member being movable to'aposition such as to render said resilient means ineffective to move saidlever.

18. In a magneto, having two sets of mag netic pole pieces and anarmature for each set movable into and out of contact therewith, saidarmatures disposed in s aced parallel relation, :1 pair of levers one oreacharmature and connected thereto for moving the same,-each lever beingpivotally supported at a point beyond one end of its armature andextending alongside its armature to and beyond the other end of thesame, a drive shaft the axis of which lies ina plane between saidlevers, and means for operating said levers at properly timed intervalsfrom said common drive shaft including means engageable with the lastnamed ends of said levers.

19. In a magneto, having two sets of ma netic pole pieces and anarmature for eac set movable into and out of contact therewith, saidarmatures disposed in spaced parallel relation a pair of levers one foreach armature and connected thereto for moving -the same, each leverbeing pivotally supported to turn about a common axis at a point beyondone end of its armature and extending alongside its armature to and beyondthe other end of the same, a drive shaft the axis of which lies in aplane between said levers and common driving means for both said leversoperating on the free ends thereof and located adjacent each other andbeyond the last named ends of the armatures.

20. In a magneto, having vtwo sets of magnetic pole pieces and anarmature for each set movable into and out of contact therewith,-saidarmatures disposed in spaced par-r allel relation, a pair of levers onefor each armature and connected thereto for moving the same, each leverbeing pivotally supported at a point beyond one end of its armature andextending alongside its armature to and beyond the other end of thesame, a

drive shaft the axis of which lies in a plane between said levers, across lev'er carried by the free end of each first named lever, theinner ends of both cross levers disposed adjacent to each other and saiddrive shaft,

and means on the latter for operating said armature and connectedthereto for moving the same, each lever being pivotally supported at apoint beyond one end of its armature and extending alongside itsarmature to and beyond the other end of the same, a drive shaft the axisof which lies in a plane between said levers, a cross lever carried bythe free end of each first named lever, the inner ends of both crosslevers'dis'posed adjacent to each other and said drive shaft, a fulcrummember for each cross lever disposed near the outer end thereof, andmeans on the drive shaft for operating said cross levers in properlytimed relation.

22. In a magneto, having two sets of magnetic pole pieces and anarmature for each set movable into and out of contact therewith, saidarmatures disposed in spaced par-. allel relation, a pair of levers onefor each armature and connected thereto for moving the same, each leverbeing pivotally supported at a point beyond one end of its armature andextending alongside its armature to and beyond the other end of thesame, a drive shaft the axis of which lies in a plane between saidlevers, a cross lever carried by the free end of each first named lever,the

inner ends of both cross levers disposed adjacent to each other and saiddrive shaft, a fulcrum member for each cross lever disposed near theouter end thereof, resilient means capable of acting on the outer end ofeach cross lever, and means on the drive shaft for operating said crosslevers in properly timed relation, said fulcrum members being shiftableto render said resilient means effective or ineffective to operate saidlevers as desired.

23. In a magneto, having two sets of magnetic pole pieces and anarmature for each set movable into and out of contact therewith, saidarmatures disposed in spaced parallel relation, a pair of levers one foreach armature and connected thereto for moving the same, each leverbeing pivotally supported at a point beyond one end of its armature andextending alongside its armature to and beyond the other end of thesame, a

drive shaft the axis of which lies in a plane between said levers, across lever carried by the free end of each first named lever, the innerends of both cross levers disposed adjacent to each other and said driveshaft, a fulcrum member for each cross lever disposed near the outer endthereof, resilient means capable of acting on the outer end of eachcross equally limiting the shifting movement of said fulcrum members.

24-t. Ina magneto, of the type wherein an armature is moved into and outof contact with magnetic pole pieces, mechanism for moving the armatureout of contact with its pole pieces against the restraining force ofmagnetic attraction, said mechanism comprising, a lever connected at apoint intermediate its ends to the armature and pivotally mounted at apoint beyond one end and extending beyond the opposite end of the sameto be operated by a driving force, whereby a long arm is availablepermitting a reduction in the driving force necessary to pry thearmature off its pole pieces, a cross lever pivotally supportedintermediate its ends on and extending crosswise of the first lever nearthe free end thereof, means for applying a driving force to one end ofsaid cross lever, and means serving as a fulcrum for the latter duringthe application of said force, whereby the force applied to said crosslever is in creased when transmitted to the first named lever and theforce/applied tocthe latter is still further increased when, transmittedto the armature, whereby the latter may be pried off its pole pieceswith a relatively small driving force.

25. In a magneto, of the type wherein an armature is moved toward andaway from magnetic pole pieces, a lever pivotally supported at one endand at a point intermediate lever pivoted to the first lever near thefree "end thereof and extending substantially transverse thereto, a camto operate said second lever, and means interposed between said cam andsecond lever to relieve the latter from the thrust imparted by said cam.

26. Ina magneto, of the type wherein an armature is moved toward andaway from magnetic pole pieces, a lever pivotally supported at one endand at a point intermediate its ends serving to support the armature, alever pivoted to the first lever near the free end thereof and extendingsubstantially transverse thereto, a cam to operate said second lever, acam follower interposed between said-cam and second lever with which thelatter is slidingly engaged, an arm pivoted at one end and to the otherend of which said follower is fixed, said arm extending in substantiallythe same direction as the second lever and serving to take the thrustimparted by said cam which thrust would otherwise tend to displace thesecond lever longitudinally and thereby exert a lateral thrust on thefirst named lever. Y

27. In a magneto, of the type in which an armature is moved toward andaway from magnetic pole pieces, mechanism for moving said armatureincluding a driving member and a plurality of multiplying leversinterposed between said member and the armature for increasing arelatively small force applied by said driving member so that it isadequate for moving said armature.

28. In a magneto, of the type in which an armature is moved toward andaway from magnetic pole pieces, mechanism for moving said armatureincluding a driving member and a plurality of multiplying leversinterposed between said member and the armature for increasing arelatively small force applied by said driving member so that it isadequate for moving said armature, and a single device efiective byadjustment to move the several parts of said mecahnism into closeoperating contact, whereby impacts between said parts are avoided inoperation.

29. Armature actuating means for a magneto, comprising in combinationwith a reciprocable armature thereof, a lever extending generallycrosswise with respect to the armature and having intermediate its endsa pivotal bearing movable with the armature, means for applying adriving force to said lever near one end, and a member for engagementwith said lever near its other end to serve as a fulcrum therefor.

30. Armature actuating mechanism for a magneto, comprising incombination with the reclprocable armature thereof, a lever extendinglengthwise ofthe armature and fulcrummed beyond one end thereof, saidlever at an intermediate point in its length being connected to move thearmature and extending beyond the opposite end thereof, a lever engagedwith the free end of the first lever and disposed substantiallytransverse thereto, a fulcrum for said second lever, and means forapplying a driving force to said second lever.

31. In a magneto, .having two magnetic circuits including two sets ofmagnetic pole pieces, armatures one for each set of pole pieces adaptedfor movement into and out of contact therewith, means for moving firstone and then the other armature away from its pole pieces, elastic meanstending to move the armatures toward their pole pieces, and means forpreventing each armature from being moved into contact with its polepieces under the action of said elastic means until the other armaturehas been moved out of contact with its pole pieces and commenced itsflight away from the same.

32. In a magneto, having two magnetic of contact therewith, elasticmeans tending to move each armature toward its pole pieces, a driveshaft, driving means oper able by an inelastic transmission of .forcefrom the drive shaft to move the armatures away from their respectivepole pieces in succession and arranged so that both armatures cannotcontact with their pole pieces at the same time, elastic driving meansfor optional use in conjunction with the first named driving means inmoving the armatures away from their pole pieces and effective to startthe armatures at later points in the revolution of the drive shaft thanwhen the. first named driving means is used alone, whereby one armaturetends to move back into contact with its pole pieces before the otherarmature has started away from its pole pieces, and means for arrestingeach armature in its flight toward its pole pieces until the otherarmature has been started in its flight away from its pole pieces. I

- 33. In a magneto, having two magnetic circuits including two sets ofmagnetic pole I pieces, armatures one for each set of pole piecesadapted for movement into and out of contact therewith, means foroperating the armatures arranged to move first one and then the otherarmature away from its pole pieces, and means for arresting eacharmature in its movement toward its pole pieces and holding it space-daway from the same until the other armature has started its movementaway from its pole pieces.

34. In a magneto, having two magnetic circuits including two sets ofmagnetic pole pieces, armatures one for each set of pole pieces adaptedfor movement into and out of contact therewith, means for operating thearmatures arranged to move first one and then the other armature awayfrom its pole pieces, and means for preventing each armature from beindrawn into contact with its pole pieces until the other armature hasbeen started in its flight away from its pole pieces.

35. In a magneto, having two magnetic circuits including two sets ofpole pieces, two independentl movable armatures, one for each set of o epieces and each adapted to reciprocate etween a position wherein thereluctance if its magnetic circuit is relatively small to a positionwherein such reluctance is relatively large, means for operating saidarmatures in succession, and means independent of said operating meansfor preventing each armature from moving back into the first namedposition until the other armature has started to move from its firstnamed position towards its second named position.

36. In a magneto, having two sets of magnetic pole pieces and anarmature for each a cross lever pivotally mounted on each lever beyondthe last named end of its armature, and means on the drive shaft foractuating the cross levers in groper timed relation.

In testimony w ereof I have aflixed my signature.

- IRA E. HENDRICKSON.

